Mechanically competent scaffold for rotator cuff and tendon augmentation

Abstract

A device has been developed to augment the rotator cuff tendon tissue as it proceeds in healing. The device has two purposes: to provide initial stability to the rotator cuff repair site to allow early mobilization of the upper extremity of the patient, and to allow for reinforcement of rotator cuff tendon repairs to increase the likelihood of successful rotator cuff tendon repairs. The device consists of an inter-connected, open pore structure that enables even and random distribution and in-growth of tendon cells. The braided structure allows for distribution of mechanical forces over a larger area of tissue at the fixation point(s).

We claim: 
     
       1. A device for repair or augmentation of rotator cuff tissue comprising
 A three dimensional braided scaffold consisting of polymeric fibers plied to create multifilament yarn bundles, wherein the yarn bundles are braided to form the scaffold, wherein the polymeric fibers are degradable polymers selected from the group consisting of poly(L-lactic acid) or (PLLA), poly(lactic acid) or (PLA), poly(lactic-co-glycolic acid) or (PLGA), polyhydroxyalkanoates and silk, wherein the polymeric fibers which form the yarn bundles have a diameter between 50-150 microns, 
 the scaffold forming an inter-connected, open pore structure that enables even and random distribution and in-growth of tendon cells and which provides structural and mechanical support for a period of about nine to twelve months following implantation and attachment at a site in or adjacent to the rotator cuff of an individual in need thereof, 
 the scaffold comprising fixation point(s) to affix the scaffold to the soft tissue or to bone adjacent to or associated with the rotator cuff soft tissue to be repaired, wherein the scaffold has a length between 10 mm and 100 mm and width between 10 mm and 100 mm, 
 wherein the scaffold distributes mechanical forces across and lengthwise over the tissue at the fixation point(s) and allows shoulder mobility while healing, and has an initial stiffness between 20 and 500 N/mm at the time of implantation. 
 
     
     
       2. The device of  claim 1  having a peak load strength between 20 and 1000 N. 
     
     
       3. The device of  claim 1  having a porosity between 50% and 70%, and pore size between 177 μm and 250 μm. 
     
     
       4. The device of  claim 2  with an initial stiffness between 20 and 80 N/mm. 
     
     
       5. The device of  claim 1 , wherein the device is seeded with cells, ingrowth of which is supported by the scaffold. 
     
     
       6. The device of  claim 5  wherein the cells are selected from the group consisting of mesenchymal cells, cells generating mesenchymal cells, fibroblasts, pluripotent stem cells, and multipotent stem cells. 
     
     
       7. A method for repairing or augmenting a damaged rotator cuff tendon or ligament in a patient comprising implanting at a site of a damaged tendon or ligament the device of  claim 1  for repair or augmentation of rotator cuff tissue. 
     
     
       8. The method of  claim 7  wherein the device has a peak load strength between 20 and 1000 N. 
     
     
       9. The method of  claim 7  wherein the device has a porosity between 50% and 70%, and pore size between 177 μm and 250 μm. 
     
     
       10. The method of  claim 8  wherein the device has an initial stiffness range between 20 and 80 N/mm. 
     
     
       11. The method of  claim 7 , wherein the device is seeded with cells, ingrowth of which is supported by the scaffold. 
     
     
       12. The method of  claim 11  wherein the cells are selected from the group consisting of mesenchymal cells, cells generating mesenchymal cells, fibroblasts, pluripotent stem cells, and multipotent stem cells. 
     
     
       13. The method of  claim 7  wherein the three dimensional braided scaffold is formed by braiding yarn bundles of plied multifilament polymeric fibers. 
     
     
       14. The method of  claim 13  wherein the scaffold is braided from yarn bundles containing 60-100 denier multifilament polymeric fibers, wherein the multifilament polymeric fibers are plied from 20 to 40 polymer filaments. 
     
     
       15. A kit comprising the device for repair or augmentation of rotator cuff tissue of  claim 1  and means for attachment. 
     
     
       16. The device of  claim 1  wherein the scaffold is braided from yarn bundles containing 60-100 denier multifilament polymeric fibers, wherein the multifilament polymeric fibers are plied from 20 to 40 polymer filaments. 
     
     
       17. The device of  claim 1  wherein the scaffold is formed by braiding multifilament polylactide fibers having a denier between 60-100. 
     
     
       18. The device of  claim 17  wherein the scaffold is formed of 75 denier poly-L-lactide multifilament fibers.